docs: def _determine_rotated_logfile(self):
          """
          We suspect the logfile has been rotated, so try to guess what the
          rotated filename is, and return it.
          """
          rotated_filename = self._check_rotated_filename_candidates()
          if rotated_filename and exists(rotated_filename):
              if stat(rotated_filename).st_ino == self._offset_file_inode:
                  return rotated_filename
  
              # if the inode hasn't changed, then the file shrank; this is expected with copytruncate,
              # otherwise print a warning
              if stat(self.filename).st_ino == self._offset_file_inode:
                  if self.copytruncate:
                      return rotated_filename
                  else:
                      sys.stderr.write(
                          "[pygtail] [WARN] file size of %s shrank, and copytruncate support is "
                          "disabled (expected at least %d bytes, was %d bytes).\n" %
                          (self.filename, self._offset, stat(self.filename).st_size))
  
          return None